Monday, December 10, 2012

During these days I am playing a bit with the data from Catalhoyök and Uppåkra, in both cases I am experimenting with Image Based Modeling techniques and Arcscene 10, with the goal to have a clear idea on what the limits and potentialities.
After a long discussion with Camilla Mazzucato from Oxford University we started implementing more models and we are planning -together with a larger group of researchers- to start working on the design of a new typology of database.
So far we grouped the models in multi patch files, but I am not jet sure if this will be the best or the only solution for this project, in fact it depends a lot from the typology of visualization that we want to reach.

3D models realized during the excavation season 2012 in Catalhöyuk

Next spring's main goal, it will be the import of the entire dataset of models realized during the last excavation season, with the goal of start working on new workflows to combine into ArcGis data of different typology (vector+3D models etc). In particular I would like for the next excavation season to explore the possibility to have a 3D distribution of findings (as points) visualized on the 3D models, let's see how far we will go..

Wednesday, November 14, 2012

At the
end of May I went to Belize to work at a Maya site out in the jungle for three
weeks. The site, originally referred as “Awe Caves”, is a medium-sized Maya
ceremonial center located in the western part of Belize. It is of particular
interest because a large cave with an extensive dark zone tunnel system resides
directly beneath the largest temple in the site core. The project of 3D
documentation and reconstruction of this site is part of a larger research
project of preliminary investigation started in the summer 2011 and directed by
Holley Moyes, UC Merced. The first year some 3D documentation of the
excavations was done by Fabrizio Galeazzi, UC Merced. This year one of the
ambitions was to 3D-scan the complete cave. The cave is a natural geological
structure, but has been divided into nine chambers in succession, by the Mayan
people. The cave turns around so that the last chamber enters into the first,
about 10-15 meters up on one of the walls in the entrance chamber. The
different division of the chambers varies from clearly manmade structures to
more or less natural boundaries.

Snapshot from pointscloud. The colored area shows a manmade wall

The 3d
scanning was done with a Faro Focus 3D scanner. It is a small and compact
scanner, that is easy to carry and has everything needed to scan built in. Faro
Focus 3D including tripod, weighs about 8 kg and is therefore the ideal scanner
for a mission of this kind. One important benefit from the small format of the
scanner is evident in the fact that the scanning of the complete cave were made
in just eight days.

Scanning of excavtion in the cave was done with light

Right
from the beginning it was decided not to try to capture color information in
the cave, but only settle for the geometry. To capture color information would
demand large amounts of lights to illuminate the cave properly. Bringing enough
lights and spending time placing them as good as possible would have been a
huge and costly task far beyond the scope of the project.

At the start
of the campaign, a fairly normal scanning strategy for larger structures was
applied. This was a relatively efficient approach in the entrance chamber, but
further into the cave it got more and more difficult. With such an extremely
irregular geometric structure found in the cave, the risk to miss important
parts was much larger than usual. So after a few days the scanning strategy
significantly changed and scanning positions were moved closer together to be
sure to cover as much as possible. It culminated in the fifth chamber, which
was a complete jumble of rocks, stalactites, stalagmites, narrow cavities and
hidden structures. This complex geometry led to a scanning strategy, in which
the different scan positions were placed only a few meters from each other.
This of course gave us a huge amount of scans that, at this writing, still
isn’t fully post processed.

The humidity caused other problems as well

Another
objective of the scanning campaign was to verify how well the scanner handled
the very special climate prevailing in a place like this. This is subtropical
jungle and the work were made during a time of year when it was quite a lot of
rain, high humidity and relatively warm. Inside the cave the temperature was
slightly lower, but the humidity was significant. Anyone who has worked with
electrical equipment in these conditions can tell you that humidity plays
tricks with equipment that does not occur in dryer environments.

Scanning part of the entrance from a spot in the jungle

We were
pleased to see that the scanner handled these conditions well for most of the
time. The battery ran out faster than usual, but that was expected. The only
problem experienced was that the touch panel of the scanner stopped working on
a number of occasions. The touch panel is mainly used to adjust the settings
for the different scans, such as resolution or whether the scan should be done
with color or not. Once these settings are made, the need to use the touch
panel is not that big, with the very important exception of starting each new
scan. Hence a non-functioning touch screen could be a serious problem.
Fortunately, the scanner also provides a more stable button under the touch screen,
which can be used just to start scans if you cannot start them otherwise. That
saved a lot of time, since the only way to get the touchscreen to work again
was to turn the scanner off and let it rest for a couple of hours. To prevent
problems with humidity,
the scanner bag was equipped with several small bags of silica gel during the entire periodin Belize.It
is used as a desiccant to control local humidity and may havedone somegood in keeping the scanner in such
a good shape.

All in all it was a very interesting trip and we are
really looking forward to have time to work with the data.

Scan of the entrancecave. To the left of the middle you can see two people that happened to be scanned. Good to use as a reference

Tuesday, October 30, 2012

I just come back from a very short archaeological mission in Cencelle (figure 1), where together with Stefan Lindgren and Doriana De Padova we joined the excavation team leaded by the Prof. Francesca Romana Stasolla, and her collaborators: Dr. Sergio Del Ferro, Dr. Lorenzo De Lellis and Dr. Lara Tonizzo Feligioni.

Figure 1 Archaeological excavation of Cencelle, Tarquinia

Cencelle is a middle age town founded by Leone IV during the IX century with the aim to provide a safe refugee to the inhabitants of Centumcelle (Civitavecchia).

Centumcelle was an ancient town along the costs few miles north of Rome, which in that period was constantly under the attack of the Saracens. Cencelle is amazing, the landscape is beautiful and the site incredibly rich.

The excavation is under the scientific direction of the University of Rome "La Sapienza", that together with l'École française di Roma, started the excavation in the 1994. Goals during our short permanence there were: the documentation of structures no more under archaeological investigations using the laser scanner, the use of Image based modeling techniques for the documentation of the ongoing excavation (cemetery), the use of the GPS to map the site.

Our work was mainly focused on finding a work methodology that could have been easily integrated with the current system of documentation in use in Cencelle.

As previously explained, we decided to employ the Laser only for the structures that were no more under investigation, in fact, despite the efficiency of the scanner in providing resolute, accurate and precise 3D models, the time required for the data post processing would have been not sustainable.

Figure 2 Map site realized using the RTK GPS

Despite some problem with the vegetation... in two days we handled to finish the work with the scanner acquiring material that will be used in the coming months by Doriana De Padova to highlight aspects of these structures not jet studied before. At the same time, with the help of the students we started the documentation campaign of the ongoing excavation of the cemetery in order to provide material that (we hope) will help the excavation team to have a better view of the complicated relations between the different graves currently under investigation.

Detail of the cemetery, 3D model of one of the burials processed in Photoscan and visualized inMeshLab

Once again the use of this technique have been incredibly efficient, already the first day it was possible to produce dense and detailed models able to provide an extraordinary view of the spacial relations between the different features of the area under investigation.
Differently from a normal raster images or vector file, the use of 3D models provide an impressive view of the ongoing situation that can provide different perspectives, already during the excavation campaign or even after the end of the investigation. The GPS has been used to produce a quick description of the topography of the site, moreover this instrument allowed to calculate the position of Control points that will be used to geo-reference the 3d models coming from the different technologies employed during this archaeological campaign.

3D model of the cemetery processed using Photoscan and visualized in MeshLab

3D model of the cemetery processed using Photoscan and visualized in MeshLab

3D model of the cemetery processed using Photoscan and visualized in MeshLab

Tuesday, September 18, 2012

I just come back from an intense week of scanning in Pompeii, where together with Stefan Lindgren (LU), Carolina Larsson (LU), Matteo Dellepiane (CNR) and Marco Callieri (CNR) we finished the 3D acquisition of the insula V1.Last year we focused on the houses of "Cecilio Giocondo" and "Torello di bronzo" (both part of the insula) and at the end of the campaign, we found the time and the energies to acquired a large portion of the street that surround the insula. This year, even if the weather slowed down our work, we completed the acquisition of all the environments left from the previous campaign, closing in only two days the documentation of the insula (fig.1).

Figure 2 one of the rooms of Casa degli epigrammi greci,

The knowledge gained last year allowed to speed up consistently the acquisition campaign; in two days, with two teams, we collected and almost aligned approximately 200 scans. Pompeii is really an incredible site, every small room has so many different typologies of information, even if the environments are almost empty the walls are characterized by a large amount of details to document (fig.2).

During this season we mainly focused on the north-west and south-west part of the insula, acquiring environments such as: Casa deli epigrammi greci, the bakery, Caupona, etc.

These areas are characterized by small and very tall rooms, all connected each others by narrow corridors and small entrances, moreover a number of containers for storage or ovens were still in their original position -bakery or the shops- and the use of the scanner for the acquisition of these rooms was not sufficient (fig.3). In specific the containers for the storage were so close each other to do not allow any (safe) scan position. In this specific case we decide instead to acquire these elements using image based modeling techniques. This approach proved to be very successful and easy to integrate with the laser scanner data.

Figure 3 Alignment process of the Casa degli epigrammi greci

The use of just one instrument or one technique would have never been enough to gain our goal (fig.4). From my experience out in the field, I learned that does not exist any technique, technology or documentation platform able to cover entirelly the documentation of an archaeological site. Integration of technologies is the only proper way to face archaeological sites. Flexibility of methods is the only characteristic that allow archaeologist to develop a creative and dynamic research using technology.I found this campaign very challenging, the environments were not easy to document, and the constant passage of tourists did not help...

Last year we worked hard to find a good workflow to post process the data and I think that this year, with some help from our students from Digital Archaeology Course we should be ready with a complete model.

Figure 4: The Faro Focus 3D scanner inside

the oven before the scanning,

in the picture: me, Matteo Dellepiane, and Mr. P

At the end of the project, we are also planning to connect high resolute 3D models of every room with the documentation available on the website of the Swedish Pompeii Project, in order to make accessible this work for everybody.

At the end of the campaign we decided to scan our team and leave a virtual footprint of us in the insula ;-)

Sunday, September 2, 2012

I came back few weeks ago from the archaeological excavation of Çatalhöyük, Turkey
where this year I tried new experiments in the use of 3D technology to document and visualize ongoing archaeological excavations.
Last year I did tests on site using Image Based Modeling techniques to document the investigation of the building 89, in that occasion the team of the university of California Merced directed by Maurizio Forte, were running similar experiments using instead a phase shift laser scanner, they got interesting results and the use of both these techniques in the same excavation context gave us a very good feedback on how different technologies that produce similar results (resolute 3D model) obey to different work-flow of data capturing and post processing.

After this tests we gain a good knowledge on how making these tools compatible with ongoing excavations and how to manage the data in a reasonable time frame.
At the end of the first season (2011) It was possible to visualize in the same platform (MeshLab) the temporal sequence of most of the units found during the investigation, moreover thanks to a total station grid provided by the survey team who operated during that season, it was even possible to geo-reference all the models realized during the campaign.

The first year was very successful, especially for what concern the creation of a functional work flow to use during the investigation process, but very few questions about archaeological methods came out. This happened probably because we could not visualized our models in the same platform where all the other data were stored: the GIS system of the excavation.

After the first season of experiments we figured it out that Image Based Modeling techniques represent today the best solution to generate 3D models of the ongoing investigation, in fact the accuracy and precision of this methods has been proved to be more than enough for any archaeological documentation, moreover using powerful laptops it has been possible to produce in few hours (sometime even in 45 minutes) complete 3D models of the buildings.

This year together with UCM we decided to mainly use this method (image modeling techniques) for the documentation of the ongoing excavation, laser scanner technology instead was mainly employed for the documentation of the entire site with point's clouds.
From the very beginning we decided to use Image based modeling techniques on a larger scale, ...I was so much curious to understand if this method was efficent also in a such huge scale, after the first season this was obviously possible, but you know... theorizing something is not exactly the same of doing something... ;-)

The results were really interesting! In fact it has been possible to work on several buildings at the same time and geo-reference all of them in the same space, moreover with the help of Camilla Mazzucato, researcher at the university of Oxford, we handle to transform the 3D models in features and finally visualize our work into the GIS system of the excavation (Arcscene) connecting each other data coming from different seasons and different teams.
Together with James Taylor from the university of York, we started discussing how this will effect the field activities and we started brainstorming new workflows in order to integrate this approach into the documentation system in use in Catal.
At the same time an interesting discussion started also with Scott Haddow from the osteology group that experimented new ways to use this technique in osteology, here some reference from his blog.

group of 3D buildings visualized in Arcscene

Before the beginning of the campaign I had the chance to discuss with Åsa Berggren and Björn Nilsson about several possible scenarios, I think that these results represent the best starting point we could get to begin a new exciting research work.

The results of this experiment open to new questions such as: how the use of this new tool will influence our way to perceive and interpret the data? How our work will effect the investigation of other archaeologists in the future? And... who will answer these question?

In order to have a deep understanding of the problem. I think it is fundamental to bring this work more and more into the field, Çatalhöyük is not just a FANTASTIC archaeological site, but a real experimental environment, where new ideas and discussions comes out constantly

Thursday, March 29, 2012

In collaboration with the Visual Computing Lab, we are developing the data from the last acquisition campaign in Pompeii and we are using MeshLab to manage the entire workflow (from aligning to texturing). This is the first time that we experienced such a huge post processing of Laser scanner data, during the last campaign we acquired almost 2 houses, several connected environments and the roads that surround half of the insula, but so far everything is going quite smooth.

The new color projection seems very good, during these days we are texturizing the Atrium of Casa del Torello di bronze, I hope to have one of the two houses ready before summer.
This huge 3D model, once finished will be used for archeological research, application for museums, teaching etc. During Last mission we were able to acquire in few days half of the insula, During the next season (probably next october) we hope to finish completely the acquisition.

Friday, March 23, 2012

we are working a lot with this tool and the results are relly incredible, soon I'll present some preliminary result of the work that we are doing in Catal.
I think that this technology is the connection between 3D and field work